The alkylating reaction for the side chain of alkyl-substituted aromatic hydrocarbons by aliphatic monoolefins is conventionally well known (e.g., H. Pines 5, J. Am. Chem. Soc., vol. 77 (1955)). However, this method is disadvantageous in that used sodium cannot be recovered, and a large amount thereof is necessary since metallic sodium is directly added to the reaction solution and is used in a suspended state.
To avoid this disadvantage, a variety of methods have been proposed to load an alkali metal on a carrier for solidification. For example, U.K. Patent 1,269,280 and JP-A-61-221133 propose the use of a potassium carbonate loaded sodium, JP-A-62-209027 proposes the use of a potassium phosphate loaded sodium, JP-A-2-138229 (corresponding to U.S. Pat. No. 5,347,062) proposes the use of a potassium hydroxide-alumina loaded potassium, JP-A-2-178236 (corresponding to U.S. Pat. No. 5,227,559) proposes the use of an alumina loaded potassium, JP-A-3-264539 (U.S. Pat. No. 5,118,895) proposes the use of a magnesia loaded potassium, JP-A-3-227944 (U.S. Pat. No. 5,097,088) proposes the use of a magnesia-alumina loaded potassium, etc. (The term "JP-A"as used herein means "unexamined published Japanese patent application".) In these proposals, the use of aliphatic monoolefins such as ethylene, propylene and butene is examined, and the reactivity decreases in the order of ethylene&gt;propylene&gt;butene, thus the reactivity of butene is lowest.
With respect to a conventional catalyst, a catalyst in which an alkali metal is loaded on a basic, carrier has a high activity, but it is disadvantageous in that the basic carrier has such a small specific area that the alkali metal loaded thereon is not sufficiently dispersed. On the other hand, an alumina catalyst in which an alkali metal is loaded on alumina has a large specific area and shows a good dispersibility for the loaded metal. However, because of the acidic nature of alumina, the alumina catalyst cannot provide a sufficient activity for alkylating the side chain, by conventional catalyst production methods.